1. Field of the Invention
The present invention relates in general to shaft coupling structures, and more particularly to shaft coupling structures of a drive shaft or the like. More specifically, the present invention is concerned with the shaft coupling structures of a type that comprises an internally splined tubular member and an externally splined shaft member coupled in a spline-connection manner.
2. Description of the Prior Art
In FR (front engine rear drive) type motor vehicles, there is employed a drive shaft that transmits power from an engine (specifically, a transmission connected thereto) mounted on a front portion of the vehicle to the differential for the rear road wheels connected to a rear portion of the vehicle through suspension devices. To assure the power transmission from the transmission to the differential, two (front and rear) universal joints are usually used. The front joint connects the front end of the drive shaft to an output shaft of the transmission and the rear joint connects the rear end of the drive shaft to an input shaft of the differential. That is, the two universal joints serve to compensate for changes in angularity of a drive line from the transmission to the differential.
Some of the drive shafts are of a split type that comprises two parts coupled in a spline-connection manner to compensate for changes in the entire length of the drive line during movement of the vehicle.
However, drive shafts of the split type tend to produce play between the two parts due to the inherent construction thereof. In fact, the play tends to cause generation of marked noise when receiving pulsating torque from the engine and/or vibration from the vehicle body.
One of measures for overcoming such drawback has been proposed by Japanese Utility Model First Provisional Publication 60-185725. In this measure, an elastically deformable plastic piece is press-fitted between the spline-coupled portions of the two parts for eliminating or at least minimizing the undesired play. However, even the measure has failed to give satisfaction to users.